bot
(From "robot") Any type of autonomous software that operates as an agent for a user or a program or simulates a human activity. On the Internet, the most popular bots are programs (called spiders or crawlers) used for searching. They access web sites, retrieve documents and follow all the hypertext links in them; then they generate catalogs that are accessed by search engines.
A chatbot converses with humans (or other bots). A shopbot searches the Web to find the best price for a product. Other bots (such as OpenSesame) observe a user's patterns in navigating a website and customises the site for that user.
Knowbots collect specific information from websites.